1. FIELD OF THE INVENTION
The present invention pertains in general to a machine for securing a metal head on, and in closing relation to, an end of a metal drum by an operation known as "seaming", and which attaches and seals the head to the drum end by deformation and folding together of adjacent, initially lapped, peripheral portions thereof. Machines of this type are known in sundry embodiments, and which include a seaming mechanism embodying a pair of seaming rolls positioned for sequential movement into working position, and which movement is produced by cam-actuation of corresponding seaming roll supporting arm units. In certain instances, there is a separate cam employed for each arm unit, while other adaptations have employed a single cam to actuate all the seaming roll supporting arm units. In both of the above adaptations, problems have been encountered either because of complexity and cost, structural faults, or inefficient or impractical performance. The present invention was conceived in a successful effort to produce a single-cam actuated seaming mechanism which avoids the problems, or undesirable characteristics, of the prior adaptations.
2. THE PRIOR ART
U.S. Pat. Nos. 785,347; 800,425; 804,642; 821,605; 1,826,506; 1,842,447; 2,101,291; 2,104,224; 2,382,469; 3,672,317 and 4,004,529 represent the most relevant prior art known to applicants.
The above prior art--considered singly or together--does not anticipate, nor suggest as obvious, the particular structure and function of the herein-claimed seaming mechanism, and applicants have no knowledge of any prior art disclosing such particular structure and its function.